Antenna device

Abstract

Provided is an antenna device, having a small and simple configuration, which reduces connection resistance in connections between a film antenna element and a power feeding unit. An antenna device comprises a nonconductive transparent film, which is an insulating substrate having a prescribed optical transmission factor, an antenna element that is formed, upon the transparent film, from transparent conductive material, which is a conductive material having a prescribed optical transmission factor, and a non-transparent conductive power feeding wire. The transparent film and the transparent conductive material are doubled over and pressed upon a portion of one side of the antenna element, which forms a square dipole antenna, such that the transparent conductive material is on the inside, and the power feeding wire is sandwiched therein. By being doubled over, the transparent conductive material has an overlap portion, the two sides whereof electrically connect to one other.

The invention claimed is: 
     
       1. An antenna apparatus comprising:
 a conductive power feed line; 
 a film-like insulation base material that has a predetermined optical transmittance; and 
 an antenna element that is formed with a conductive material having a periodic geometric pattern structure with a predetermined optical transmittance on one surface of the insulation base material, folded together with the insulation base material to place the conductive material inside and sandwich an end of the power feed line, and electrically connected with the power feed line such that the geometrical pattern matches itself in overlapping parts where the conductive material matches itself over a predetermined range. 
 
     
     
       2. The antenna apparatus according to  claim 1 , wherein the antenna element is formed with the conductive material such that a pattern density of the geometric pattern is set higher in a part to connect with the power feed line, and is set lower following an increase of a distance from the part to connect with the power feed line.